The Dalek Prime was, according to some accounts, a senior-ranking Dalek and an alternative form of the Dalek Emperor. The title seemed interchangeable, much in the same way the Supreme Dalek was occasionally referred to as the Black Dalek.

Following the end of the Thousand Year War, the Dalek Prime began conducting experiments on other life-forms on Skaro, creating mutations which went on to inhabit the Petrified Forest and the Lake of Mutations near the foot of the Drammankin Mountains. Eventually the Dalek Prime discovered the molecules that had the ability to cause further mutation within a Dalek and created a drug from its research which would initiate the mutation. Not prepared to test the drug on any Dalek in case it grew beyond its capabilities, the Dalek Prime used the drug on itself and evolved to the peak of Dalek evolution with hugely enhanced mental powers and it proclaimed itself the Emperor of the Dalek race. (PROSE: The Evil of the Daleks)

In the year 4000, the Daleks constructed a base on the planetKembel and formed an alliance with the rulers of the Outer Galaxies to gather the resources they needed to build the Time Destructor which they planned to use to wipe out the entire Solar System. The Dalek Prime awaited the completion of the invasion on Skaro. Due to the interference of the First Doctor, the Time Destructor's taranium core was stolen. The Dalek Prime sent a Red Dalek from Skaro to Kembel in another time machine to aid in its recovery. When the taranium was recovered and returned to Kembel, the Doctor got hold of the Time Destructor and wiped out the Dalek force stationed there. The Dalek Prime, unable to replace the invasion fleet and the Black Dalek commanding it, was forced to accept the defeat. (PROSE: Mission to the Unknown/The Mutation of Time)

Much later, the Dalek Prime returned following the Imperial-Renegade Dalek Civil War and set about planning to extinguish the remaining support Davros still had within the Dalek Empire. A deal was made with a group of Thals who kidnapped Davros, along with the Eighth Doctor, and they transported him to Skaro to stand trial. Before the trial, the Dalek Prime claimed to the Doctor that much of Dalek history was a fabrication to prevent destruction of Skaro by Davros and the Seventh Doctor at the culmination of the Shoreditch Incident. During Davros's trial, one of Davros's supporters destroyed a decoy of the Dalek Prime, igniting another civil war. The Dalek Prime claimed victory after Davros's capture and apparent execution and after his supporters were apparently wiped out. (PROSE: War of the Daleks)

The Dalek Prime was pulled through the Doctor's timestream and encountering the fifth, sixth, seventh and eighth incarnations of the Doctor. He was finally trapped in a time loop created by the Fifth Doctor. (AUDIO: The Four Doctors)

The Dalek Prime's original appearance was to be the War of the Daleks TV serial proposed by John Peel. The story was never produced following the show's cancellation in 1989. Peel kept the idea and the Dalek Prime appeared or was mentioned in all of his Dalek novels and novelisations apart from The Power of the Daleks. The audio story The Four Doctors marks the Dalek Prime's only appearance in a story that was neither a novel nor written by Peel (excluding Genesis of the Daleks since it was originally a standard Dalek before future writers came up with the concept of a Dalek Prime).